Flutter Animation Tutorial: Core APIs, Concepts, and Practical Examples

Flutter Animation Tutorial

This guide systematically introduces animation in Flutter, explaining key terminology such as frames, FPS, transitions, easing, interpolators, keyframes, tweening, and physics‑based animation, and then dives into the core animation API classes.

1. Core Concepts

Animation is the rapid display of a series of static images (frames) at a fixed frequency to create the illusion of motion. Frame rate (FPS) determines how many frames are shown per second, influencing perceived smoothness.

2. Core Animation API

The most frequently used classes are Animation , AnimationController , Curve , and Tween . Their main properties and methods are listed for quick reference.

Animation

status → AnimationStatus

value → current animated value

isDismissed , isCompleted

AnimationController

duration , reverseDuration

lowerBound , upperBound

forward() , reverse() , repeat() , fling() , stop() , dispose()

Curve

Pre‑defined curves (e.g., Curves.linear , Curves.easeInOut , Curves.bounceOut ) are accessed via the Curves class. Custom curves can be created by extending Curve and overriding transform() .

Tween

Used to generate intermediate values between a begin and end value. Methods include transform() , evaluate() , animate() , and chain() .

3. Practical Examples

Several runnable code snippets demonstrate how to build common animations:

class AnimatedBox extends StatefulWidget {
  const AnimatedBox({super.key});
  @override
  State createState() => _AnimatedBoxState();
}

class _AnimatedBoxState extends State<AnimatedBox> with SingleTickerProviderStateMixin {
  late AnimationController _controller;
  late Animation<double> _animation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(seconds: 2),
      vsync: this,
    );
    _animation = Tween(begin: 0.0, end: 200.0).animate(_controller)
      ..addListener(() => setState(() {}));
    _controller.forward();
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      width: _animation.value,
      height: _animation.value,
      color: Colors.blue,
    );
  }
}

Additional snippets show how to make the animation repeat, reverse, apply custom curves, combine size, rotation, and translation animations, and use AnimatedBuilder to avoid manual setState() calls.

4. Other Useful APIs

Brief overviews of Ticker , AnimationStatus , lerp functions for various types, explicit vs. implicit animations, and a list of built‑in animated widgets (e.g., AnimatedScale , AnimatedRotation , AnimatedOpacity ).

5. Advanced Topics

Examples of physics‑based simulations ( SpringSimulation , GravitySimulation ) and a draggable card demo that returns to the center using a spring animation are provided.

6. Summary

The article equips readers with the knowledge to create simple to complex animations in Flutter, covering theory, API usage, practical code, and performance‑friendly patterns.